This year Anne Reid turns 80 and she’s rarely been busier. In the last few months, the actress has appeared in period drama Our Zoo, filmed the third series of Last Tango In Halifax, starred in the cabaret Just In Time celebrating the work of American lyricists Comden and Green, travelled to New York to promote the stage show and begun production on a hush hush TV project.

“Not bad for an old bird,” laughs Reid. “There aren’t too many parts around for people like me, I’m terribly lucky.”

That said, she was forced to reassess her schedule in 2013.

“I was doing my cabaret at the same time as Tango and it was too much. One day I came on set and I dried up so badly they had to leave the scene because I was too tired. But then I have a tendency to take on more than I can chew.

“I think it’s quite a good fault,” she adds. “People who say no all the time don’t have a very nice life.”

You can always rely on Reid to tell it as it is.

Take her relationship with Last Tango co-star Sir Derek Jacobi. Their on-screen relationship as childhood sweethearts who reunite after 60 years has been hailed as hugely influential across the TV landscape, but while Jacobi talks of an instant connection between the pair, Reid was a little more tentative.

“I met him at a lunch with the producer and first director and thought, ‘He seems like a very nice man’. I can’t say I felt trust at lunch because I don’t trust anybody.”

“People will go, ‘Oh this person is really nice’ and I think, ‘Well my neighbour’s nice but she couldn’t direct a television show’. I’ve been around too long and until I start working with somebody, you don’t know.”

She and Jacobi have since forged a terrific friendship. They dine on a nightly basis while filming and she visited him in hospital when he was recovering from a nasty injury he sustained on holiday.

She walked into his room to be met by the sight of balloons, roses “and God knows what”.

“I said, ‘I see you’re being ignored again’.”

Then there was the impromptu cocktail hour.

“He had another friend there and asked if we’d like a drink, rang down and a few minutes later, a nurse came in with a tray with three G&T’s on it. I don’t mind going into hospital if it’s going to be like that.”

Reid’s fared well with regards to her health and hopes that will continue as she’s already looking towards a fourth series of Last Tango.

“If I’m still alive,” she jokes. “I’m getting on a bit now.”

All the cast members, including Sarah Lancashire and Nicola Walker, talk of the camaraderie on set – and of course Reid relishes her BAFTA-nominated role as the bigoted Celia.

“I absolutely adore this character because she’s so multi-faceted, as people are,” says Reid. “So often you only get to play a couple of sides of somebody but with her I go, within a scene, from being foul to entertaining to kind and that’s people. It’s much easier to get right if it’s strong brush strokes and that’s why I think Shakespeare’s a doddle.

“Derek and I wouldn’t agree about that, he would be horrified, but the thoughts there are very clear. In Sally Wainwright’s work, the characters are like paintings with lots of detail. It’s a nightmare to learn and play, darling!”

Reid admits she’s come across a few Celia-types in her life.

“We’ve all met people who are charming and who you want to have dinner with. Then you suddenly get onto a subject like racism or politics and you realise you can never really be close friends with them because, underneath, their attitude is appalling.”

In a recent episode, Celia refused to go to her daughter Caroline [Lancashire] and her partner Kate’s wedding.

“I don’t think Celia will ever like the idea her daughter’s a lesbian. It’s a big thing to get your head around especially someone from my generation, because we weren’t brought up with gay people like you are now,” she continues.

“I’ve got loads of gay friends now and I ask them, ‘Is Celia being too horrible? And they go, ‘Oh no, no’ because they’ve had very bad experiences. I think unless you’re in the theatre or very broad-minded, it’s very hard for people to get used to it.”

Reid recalls how when she was a young girl “the biggest horror” for her family was to marry a Catholic. “I actually did [she married the late Peter Eckersley in 1971 with whom she had a son] but it’s absurd now. I think when my grandsons grow up, people being gay will not be one thing or the other.”

As “monstrous” as Celia can be, the actress, who was BAFTA-nominated for the TV drama The Mother in 2004, hopes she never comes around the idea because in reality people like her don’t.

“She tries, but I think it’s so ingrained in her not to approve of it, I think it’s an emotional thing. Your brain can say, ‘I’m going to be sensible about this’, but emotionally it’s too deep that it’s not normal for two women to sleep together and have sex. She can’t get her head around it.”

Reid couldn’t be further from her alter-ego. “The world is changing so fast and thank God. We’re this little bit of a pea floating about in space and we worry about who sleeps with who,” she exclaims. “I don’t give a wotsit. It’s got nothing to do with me. And as long as it doesn’t impinge on my life, why would I care? Why do people become so irate? Daft really isn’t it?”

n Anne Reid is currently starring in Last Tango In Halifax